Finally, in all countries though with diversities due to national peculiarities, the modes of account and control have been brought into a more effective condition.
Yet the general agreement of solar and stellar chemistry does not exclude important diversities of detail.
There ensued a general classification of the stars by Secchi into four leading types, distinguished by diversities of spectral pattern; and the recognition by Huggins of a considerable number of terrestrial elements as present in stellar atmospheres.
C. Vogel published a modification of Secchi's scheme of stellar diversities, and gave it organic meaning by connecting spectral differences with advance in " age."
Apart from the botanical interest of these diversities, as indications of the faculty of variation in plants, and possibly as clues to the genealogy and origin of the cultivated plant, their practical importance is very great.